The present invention relates to valves in general, and more particularly to valves (hereinafter also called rotary distributor valves) wherein the valving element can be indexed in the housing or body to direct a single stream of incoming fluid into any one of several outlets or to direct fluid from any one of several inlets into a single outlet. Still more particularly, the invention relates to improvements in valves wherein the valving element can be adjusted to connect a pair of inlets with selected outlets or to connect a selected one of several outlets with an inlet, for example, to convey a stream of liquid which contains solid particles from the bottom of a body of water to the surface.
It is well known that the components of pipe lines and valves which are used to lift solid particles from the sea bottom undergo extensive wear as a result of frictional engagement with the solids in a liquid stream. The extent of erosion progresses with increasing speed of the liquid carrier medium, and the erosion is concentrated primarily in those areas where the solid particles are forced against the internal surfaces of pipe lines and/or valves under the action of gravity and/or centrifugal forces. On the other hand, underwater valves and pipe lines should be capable of standing long periods of use without any inspection and/or maintenance, especially when they are used in systems of the type disclosed, for example, in the commonly owned U.S. Pat. Nos. 3,753,303 and 3,842,522 respectively granted on Aug. 21, 1973 and Oct. 22, 1974 to Holzenberger et al. The disclosures of these patents are incorporated herein by reference. Many valves of the system which is disclosed in the patents to Holzenberger et al. are continuously traversed by streams of water which carries particles of ore or other solid substances. Note the valves 18, 19 in FIGS. 3 and 4 of the patents to Holzenberger et al. Therefore, such valves must be designed to enable their components to stand long periods of use because they are not readily accessible and any attempts to inspect and/or replace their parts would entail prolonged interruptions of the underwater mining operation. Solid particles are especially likely to accumulate in narrow clearances between stationary and moving parts, e.g., between the housing and the valving element of a valve. The liquid carrier medium cannot properly rinse such clearances so that any particles of ore which enter the clearances are likely to remain therein and to cause rapid wear upon the adjacent surfaces of the stationary as well as movable parts. Solid particles are further likely to accumulate in so-called dead spaces or in regions where the speed of the liquid carrier medium is reduced due to the design of surfaces surrounding the path for the flow of liquid which contains solid particles.